Effects of Different Annealing Gases on Pentacene OTFT With HfLaO Gate Dielectric

Abstract

Pentacene organic thin-film transistors (OTFTs) with HfLaO high-κ gate dielectric were fabricated. The dielectric was prepared by a sputtering method and then annealed in N2, NH3, O2, or NO at 400 °C. The carrier mobility of the NH3-annealed OTFT could reach 0.59 cm2/V · s, which is higher than those of the other three devices. Moreover, the NH3-annealed OTFT obtained the smallest subthreshold swing of 0.26 V/dec among them. Furthermore, 1/f noise measurement indicated that the NH3-annealed OTFT achieved the smallest 1/f noise. All these should be attributed to the improved interface between the gate dielectric and the organic semiconductor associated with the passivation effects of the NH3 annealing on the dielectric surface.